Birth Control Pill's Link To Breast Cancer Disputed

September 25, 1996|By New York Times News Service.

NEW YORK — Since its introduction in the 1960s, the birth control pill has been controversial, most recently because of several studies associating it with breast cancer. Now, an exhaustive analysis of nearly all of the studies on the subject has concluded that the pills do not increase the long-term risk of the disease.

In the past, some studies suggested increased risk, and others did not. This study builds the strongest case to date that oral contraceptives do not cause breast cancer, said Carolyn Westhoff, associate editor of the journal Contraception, which devoted the entire September issue to the report. A shorter version of the study was published in June in The Lancet, an international medical journal published in Britain.

The analysis was conducted by researchers from 25 countries and looked at 54 epidemiological studies involving 53,297 women with breast cancer and 100,239 healthy women. The research represents about 90 percent of all the worldwide epidemiological evidence on breast cancer risk and birth control pills.

"For the pill, the most critical safety issue has been breast cancer," said Westhoff, who is also an associate professor of obstetrics and gynecology at the Columbia University School of Public Health.

"Before this huge analysis was published, I don't think most clinicians felt confident that they could tell women not to worry about breast cancer. Now doctors can reassure their patients."

A number of studies in the last 13 years have shown elevated breast cancer rates in users of birth control pills, especially those in their 30s and 40s. A study published last year in The Journal of the National Cancer Institute showed a slightly higher incidence of the disease in women under 45 who had used oral contraceptives, compared with women who had never used them.

The new analysis, which included last year's study, found that 10 years after going off birth control pills, women who had used them were at no higher risk of breast cancer than women who had not.

The finding held true regardless of hundreds of variables, including a woman's age when she started and stopped with birth control pills, the number of years she took them, her family history of breast cancer, the type of pills used and the dose.

The analysis did find a slightly increased incidence of breast cancer in women while they were taking oral contraceptives and for 10 years after discontinuing their use.

Oral contraceptives also have been linked to higher risk of some cardiovascular problems, the FDA says, and are not recommended for smokers over 35.